Comparative mycotoxin profiles of gibberella zeae populations from barley, wheat, potatoes, and sugar beets
Gibberella zeae is one of the most devastating pathogens of
barley and wheat in the United
States. The fungus also infects noncereal
crops, such as potatoes and sugar beets, and the genetic relationships among
barley, wheat, potato, and sugar beet isolates indicate high levels of
similarity. However, little is known about the toxigenic potential of G. zeae
isolates from potatoes and sugar beets. A total of 336 isolates of G. zeae from
barley, wheat, potatoes, and sugar beets were collected and analyzed by TRI
(trichothecene biosynthesis gene)-based PCR assays. To verify the TRI-based PCR
detection of genetic markers by chemical analysis, 45 representative isolates
were grown in rice cultures for 28 days and 15 trichothecenes and 2 zearalenone
(ZEA) analogs were quantified using gas chromatography-mass spectrometry.
TRI-based PCR assays revealed that all isolates had the deoxynivalenol (DON)
marker. The frequencies of isolates with the 15-acetyl-deoxynivalenol (15-ADON)
marker were higher than those of isolates with the 3-acetyl-deoxynivalenol
(3-ADON) marker among isolates from all four crops. Fusarium head blight
(FHB)-resistant wheat cultivars had little or no influence on the diversity of
isolates associated with the 3-ADON and 15-ADON markers. However, the frequency
of isolates with the 3-ADON marker among isolates from the Langdon, ND,
sampling site was higher than those among isolates from the Carrington and
Minot, ND, sites. In chemical analyses, DON, 3-ADON, 15-ADON, b-ZEA, and ZEA
were detected. All isolates produced DON (1 to 782 µg/g) and ZEA (1 to 623
µg/g). These findings may be useful for monitoring mycotoxin contamination and
for formulating FHB management strategies for these crops.
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